CN108028566B - Cooling of rotating electrical machines - Google Patents

Abstract

The invention relates to a rotating electrical machine (1) comprising a rotor (3) rotatable about an axis of rotation (4), the rotor having a rotor tube (3b) and a shaft end (7), wherein the shaft end (7) is arranged On the non-drive side (NDE) of the rotating electrical machine (1) and in which the rotor tube (3b) is mechanically connected to the shaft end (7) at the axial end of the rotor tube (3b). It is proposed to save space and costs that the shaft end (7) has a central hole (7b) and/or parallel holes (7c) for supplying a cooling medium (19) into the rotor tube (3b). The rotor tube (3b) has at least one cooling opening (3c), and wherein the central hole (7b) and/or the parallel holes (7c) are in fluid communication with the at least one cooling opening (3c).

Description

Cooling of rotating electrical machines

technical field

The invention relates to a rotating electrical machine having a rotor rotatable about an axis of rotation, the rotor having a rotor tube and a shaft end, wherein the shaft end is arranged on the non-drive side of the rotating electrical machine, and wherein the rotor tube is in the axial direction of the rotor tube The end is mechanically connected to the shaft end.

The invention also relates to a pod drive with at least one such rotating electrical machine.

Furthermore, the invention relates to a watercraft with at least one such pod drive.

In addition, the invention relates to a method for cooling such a rotating electrical machine.

Background technique

Such rotating electrical machines, such as motors or generators, are preferably present in propeller pod drives, also referred to below as POD drives or pod drives. Such a rotating electric machine in a POD drive preferably has a power of at least 5 megawatts and is implemented, for example, as a permanent magnet synchronous machine. The number of revolutions is preferably in the range of 50 rpm to 250 rpm.

The rotary motor of the propeller pod drive is preferably covered with the pod's flow-friendly casing and mounted eg on a boat, preferably rotatable by 360 degrees about a vertical axis. Furthermore, pod drives can advantageously be used in submarines or propeller-driven aircraft.

In the case where the electric drive is positioned, for example, in seawater outside the hull, the heat losses generated in the rotating electrical machine must be dissipated in a suitable form. So far, at least most of the losses are discharged into seawater by convection via the surface of the shell. The rest of the resulting heat losses, especially at locations where the housing is not directly connected to the water surrounding the drive, are currently partly via complex air guidance (for example via the winding heads of the stator lamination stack on one side) Through the air gap or shaft, through the machine via the air channel until the conical carrier and the heat exchanger placed there dissipate.

European patent EP 2420443 B1 discloses a pod drive for a levitation device, comprising an underwater housing flowed around by water, having a propeller shaft rotatably supported therein with at least one arrangement a propeller thereon; and, an electric motor for driving the propeller shaft disposed in the underwater housing, the electric motor having a stator and a rotor, wherein a space is formed between the stator and the underwater housing, the space Delimited at least in part by the stator and a part of the submerged housing and in this space a cooling liquid flows for cooling the motor, wherein the space is closed to the water flowing around the submerged housing and achieves heat transfer from the stator via The transfer of the cooling liquid flowing in the space to the submerged shell section bounding the space and from there to the water flowing around the submerged shell. All of the motor heat is dissipated by the cooling liquid in the space to the submerged shell section bounding the space and from there to the water flowing around the submerged shell.

European patent EP 0 907 556 B1 discloses a marine drive which consists of a housing arranged in a pod-like manner on the underside of the hull, the housing having a synchronous motor in the housing. In order to improve the propulsion efficiency at a drive power of approximately 10 MW, the rotor of the synchronous motor is designed as a permanently excited rotor, and the stator of the synchronous motor is fitted into the housing in a form-fitting manner for cooling through the housing wall. Here, additional cooling devices in the form of fans or spray devices can be assigned to each winding head.

A device for self-sufficient cooling of the rotor of a pod propeller with one or two electric motors is disclosed in the publication DE 10000578 A1. The device uses a propeller cap with a central cooling water inlet and peripheral coaxial outlets, where the hot cooling water is expelled by centrifugal force. It is cooled by the rotor housing and the ducts through the active rotor core.

The publication EP 0 590 867 A1 discloses a main drive facility for a high-power engine ship or other large seagoing vessels. The main drive has a housing comprising a tubular shaft and a spherical portion, wherein the lower portion is connected to the tubular shaft and is rotatable therewith. The housing has an inner cavity in the spherical portion containing the electric drive motor and a propeller shaft connected to at least one propeller external to the housing. A cooling line is arranged axially in the propeller shaft, wherein ambient water can flow through this line.

In publication EP 2 757 666 A1 a rotating electrical machine with a stator and a rotor arranged in a housing is disclosed. The rotor has at least one rotor coolant guide plate with at least one radially outward opening in the axial central region of the rotor, through which the coolant in the rotor can be guided radially outwards to the rotor peripheral surface of the inner surface.

Publication US 2015/0048699 A1 discloses a rotor for a high-speed generator having a rotor body with inner and outer surfaces, a coolant inlet and outlet, and a rotor cooling path for cooling the rotor body.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a rotating electrical machine which saves space and costs compared to the prior art.

According to the invention, this object is achieved by a rotating electrical machine having a rotor rotatable about an axis of rotation, the rotor having a rotor tube and a shaft end, wherein the shaft end is arranged on the non-drive side of the rotating electrical machine, wherein , the rotor tube is mechanically connected to the shaft end at the axial end of the rotor tube, and wherein the shaft end has a central and/or parallel bore provided for supplying cooling medium to the rotor A tube, wherein the rotor tube has at least one cooling opening, and wherein the central bore and/or the parallel bore are fluidically connected to the at least one cooling opening.

The cooling medium can also be a gaseous cooling medium, such as air or an inert gas, or a liquid cooling medium, such as water or oil. The parallel holes extend parallel to the axis of rotation. The advantage of the invention is, in particular, that the supply of coolant is simplified. This saves space and saves costs.

Furthermore, this object is achieved by a pod drive having: at least one such rotary electric machine; a first bearing arrangement on the non-drive side of the rotary electric machine; a second bearing on the drive side of the rotary electric machine a device; and a propeller, wherein the propeller is connected to a drive shaft of the rotating electric machine.

This is particularly advantageous because in this way a very compact and space-saving pod drive is achieved.

Furthermore, the object is achieved by a vessel having at least one such pod drive and a first heat exchanger arranged outside the pod drive, wherein the first heat exchanger is provided for supplying the pod drive with a cooling medium And the cooling medium flowing out of the pod drive is cooled again.

This results in efficient cooling and space savings in the pod drive.

Furthermore, this object is achieved by a method for cooling such a rotating electrical machine, wherein, firstly, a cooling medium is guided in the axial direction through a central hole and/or a parallel hole at the shaft end into the rotor tube, after which it is It is guided in the radial direction through cooling openings arranged in the axial center of the rotor tube and the rotor lamination stack, after which the guided cooling medium passes through the air gap and/or between the rotor tube and the rotor lamination stack are guided to the axial ends of the rotor, and thereafter, the guided cooling medium is guided in the radial direction past the stator winding heads.

This method for cooling is particularly advantageous because a uniform distribution of the cooling medium in the rotor is achieved. Furthermore, the supply of coolant is simplified, which leads to space and cost savings.

In a particularly advantageous manner, the central hole is arranged to extend in the axial direction through the axis of rotation. Thereby, the shaft ends are preferably rotationally symmetrical, which results in a good stability of the cooling medium and a uniform supply.

Advantageously, the parallel holes are arranged to extend in the axial direction around the axis of rotation. For example, the parallel holes are arranged concentrically around the axis of rotation. This results in an even distribution of the cooling medium in the rotor.

In a preferred embodiment, the shaft end is connected to the rotor tube via a first shrink fit or via a first flange connection. In the case of a flange connection, the shaft end is designed, for example, in such a way that it is connected to the rotor tube by means of screws and/or welding. In the case of a shrink fit, the rotor tube is preferably heated, eg, several hundred degrees Celsius, whereby the inner diameter of the rotor tube increases due to thermal expansion (this is also referred to as thermal expansion). The shaft end is then partially inserted into the heated rotor tube. During cooling of the rotor tube, thermal shrinkage, also referred to as thermal shrinkage, occurs, whereby the rotor tube regains its previous dimensions and is connected to the shaft end in a rotationally fixed manner. This mechanical connection is space-saving, robust and cost-effective.

In a further advantageous refinement, the rotating electrical machine has a stator surrounding the rotor and an air gap between the rotor and the stator, wherein the rotor has a rotor lamination stack around the rotor tube, wherein the rotor tube and the rotor lamination stack are in their Its axial center has at least one cooling opening extending in radial direction, and wherein the cooling opening is provided for guiding the cooling medium supplied into the rotor tube through the shaft end to the air gap and/or between the rotor tube and the rotor Between the lamination stacks lead to the axial ends of the rotor. For example, the cooling medium is guided uniformly from the cooling openings to the axial ends of the rotor. This is particularly advantageous because the rotor then has a more uniform temperature distribution. Furthermore, parallel ventilation channels are realized, eg in the air gap, in the magnetic cavity, and between the rotor tube and the lamination stack, which improve cooling.

In a preferred embodiment, the rotor lamination stack has at least one permanent magnet which is arranged to be cooled by a cooling medium guided through the air gap. This is advantageous because the cooling medium cools the permanent magnets before the cooling medium is partially heated, eg by passing through the winding heads.

The permanent magnet preferably has a rare earth element fraction, in particular a dysprosium fraction, wherein the permanent magnet is arranged such that it is cooled during operation to a temperature between 70° C. and 100° C., in particular between 80° C. and 90° C. . Preferably, the permanent magnets have a relatively small fraction of rare earths due to the low operating temperature achieved, for example, by advantageous cooling. This is advantageous because of the cost savings due to the small share of rare earths.

In a further advantageous configuration, the stator has stator winding heads at the axial ends, wherein the cooling medium that is led to the axial ends of the rotor is provided for cooling the stator winding heads. This is particularly advantageous since no additional coolers are required for cooling the winding heads. This saves space and cost.

In a preferred embodiment, the rotor tube has a thickening around the cooling opening, which is provided to increase the rigidity of the rotor tube. This is particularly advantageous, whereby the thickening compensates for the weakening of the cross-sectional structure due to the cooling openings in the rotor tube.

In a further advantageous configuration, the rotor tube has a coolant-impermeable dividing wall, which is provided for guiding the cooling medium supplied through the shaft end to the cooling opening. This is particularly advantageous because, for example, the coolant supply is improved.

In a preferred embodiment, the rotating electrical machine has a first guide plate which is arranged to achieve separation between the cooler cooling medium supplied through the shaft end and the cooling medium directed to the axial end of the rotor. This is advantageous because more efficient cooling is thus achieved.

In a further advantageous configuration, the rotating electrical machine has a drive shaft which is arranged on the drive side of the rotating electrical machine, wherein the drive shaft has further parallel bores which are provided for supplying additional cooling medium into the rotor tube . The further parallel holes are preferably arranged to extend in the axial direction concentrically about the axis of rotation. The supply of additional cooling medium into the rotor tubes is particularly advantageous, since then a larger quantity of coolant can be supplied, eg by means of heat exchangers arranged on both sides, which leads to a higher overall cooling performance.

In a preferred embodiment, the rotating electrical machine has a second guide plate arranged to achieve separation between the additional cooling medium supplied by the drive shaft and the cooling medium directed to the axial ends of the rotor. This is advantageous as more efficient cooling is achieved in this way.

Preferably, the drive shaft is connected to the rotor tube via a second shrink fit or via a second flange connection. This mechanical connection saves space and is implemented in a robust and cost-effective manner.

In a preferred embodiment, the first bearing arrangement and/or the second bearing arrangement each have at least one radial bearing and an axial bearing. Preferably, the axial bearing is designed as an axial spherical roller bearing or a CARB bearing. Accordingly, the drive shaft and the shaft end each have a support bearing and a guide bearing, which improves the efficiency of the pod drive, especially in prevailing marine conditions.

In an advantageous manner, the guided cooling medium is guided symmetrically and almost uniformly to the axial ends of the rotor and to the stator winding heads. This makes the temperature distribution uniform.

Preferably, the cooling medium flowing out of the stator winding heads is guided on both sides through the stator lamination stack and converges at the axial center of the stator lamination stack. This is advantageous because the stator lamination stack is additionally cooled by the outflowing cooling medium. Furthermore, the outflowing cooling medium can be discharged in a space-saving manner in the axial center of the stator lamination stack.

In a further advantageous configuration, the additional cooling medium is guided in the axial direction through further parallel bores of the drive shaft into the rotor tube, and the cooling medium is aggregated together with the additional cooling medium in the rotor tube into two cooling medium supplied from the side. This is particularly advantageous because a larger amount of coolant is thus supplied, which improves cooling.

Description of drawings

The invention will be described and explained in detail below with reference to the embodiments shown in the accompanying drawings.

The figure shows:

Figure 1 shows a longitudinal section of a first embodiment of a rotating electrical machine,

Figure 2 shows a longitudinal section of a second embodiment of the rotating electrical machine,

Figure 3 shows a longitudinal section of a third embodiment of the rotating electrical machine,

Figure 4 shows a three-dimensional representation of the pod drive,

Figure 5 shows a three-dimensional representation of a first embodiment of a shaft end connected to a rotor tube,

Figure 6 shows a three-dimensional representation of a second embodiment of the shaft end connected to the rotor tube, and

Figure 7 shows a vessel with a pod drive.

Detailed ways

FIG. 1 shows a longitudinal section of a first embodiment of a rotating electrical machine 1 . The rotating electrical machine 1 has a rotor 3 rotatable about an axis of rotation 4 , a stator 2 surrounding the rotor 3 and an air gap 6 between the rotor 3 and the stator 2 . The axis of rotation 4 defines an axial direction, a radial direction and a circumferential direction.

The rotor has a rotor lamination stack 3a and a rotor tube 3b. A plurality of permanent magnets 21 are arranged in the circumferential direction and in the axial direction on the rotor lamination stack 3a, wherein the permanent magnets 21 are at least partially integrated into the rotor lamination stack 3a.

On the non-drive side NDE of the rotor tube 3b, the shaft end 7 is connected to the rotor tube 3b via a first shrink fit portion 7e. Furthermore, on the drive side DE of the rotor tube 3b, the drive shaft 11 is connected to the rotor tube 3b via the second shrink fit portion 11d.

The shaft end 7 has a central hole 7b and a parallel hole 7c. The parallel holes 7c extend parallel to the axis of rotation 4 . The central hole 7b and the parallel holes 7c are provided for supplying a cooling medium 19 into the rotor tube 3b. The cooling medium 19 may be a gaseous cooling medium, such as air or an inert gas, or a liquid cooling medium, such as water or oil. The central hole 7b extends through the axis of rotation 4 in the axial direction and is thus arranged rotationally symmetrically about the axis of rotation 4 . The parallel holes 7c extend in the circumferential direction around the axis of rotation 4 and in the axial direction, preferably being arranged concentrically, ie at equal distances from the axis of rotation 4 .

The rotor lamination stack 3a and the rotor tube 3b have at their axial center a plurality of cooling openings 3c extending in the radial direction, which are arranged in the circumferential direction and/or in the axial direction. For example, the cooling openings 3c are arranged at equal intervals in the circumferential direction. The cooling openings 3c are provided for guiding the cooling medium 19 supplied through the shaft end 7 into the rotor tube 3b to the air gap 6 and/or to the axial end of the rotor 3 between the rotor tube 3b and the rotor lamination stack 3a . The rotor tube 3b has a thickening 3d surrounding the cooling opening 3c, which is provided to increase the rigidity of the rotor tube 3b. The weakening of the cross-sectional structure due to the cooling openings 3c in the rotor tube 3b is compensated by the thickening.

The stator 2 has a stator lamination stack 2a and a stator winding 2c, wherein the stator winding 2c has a stator winding head 2b at the axial end of the stator 2 . The stator lamination stack 2 a has channels in order to collect the heated cooling medium 19 c flowing out of the stator winding head 2 b in the axial center of the stator lamination stack 2 a and preferably lead it out to the heat exchanger 5 .

The first guide plate 8 and the second guide plate 9 are respectively fixed partly on the rotor 3 and partly on the stator 2 and to each other via coolant-impermeable, movable/slidable connections (eg gaps) relative to each other connect. By means of the guide plates 8 , 9 a separation is achieved between the cooler cooling medium 19 supplied through the shaft end 7 and the cooling medium 19 b directed to the axial end of the rotor 3 . Furthermore, the rotating electrical machine has a casing 20 .

The cooling medium 19 produced by the first heat exchanger 5 located outside the rotary electric machine is supplied to the rotary electric machine 1 and guided in the axial direction through the central hole 7b and the parallel holes 7c of the shaft end 7 into the rotor tube 3b. Afterwards, the cooling medium 19 is guided in the radial direction through the cooling opening 3c located in the axial center of the rotor tube 3b and the rotor lamination stack 3a. Subsequently, the guided cooling medium 19b passes through the air gap 6 and is guided between the rotor tube 3b and the rotor stack 3a to the axial ends of the rotor 3, where the guided cooling medium 19b is arranged on both sides by The guide plates 8, 9 are guided in the radial direction past the stator winding head 2b. Here, the guided cooling medium 19b is guided approximately symmetrically and distributed almost uniformly to the axial ends of the rotor 3 and to the stator winding heads 2b. The outflowing cooling medium 19c is guided from both sides of the stator winding head 2b through the channels in the stator lamination stack 2a, converges in the axial center of the stator lamination stack 2a, and is preferably supplied again to the heat exchanger 5 .

FIG. 2 shows a longitudinal section of a second embodiment of the rotating electrical machine 1 . The second embodiment of the rotating electrical machine 1 basically corresponds to the first embodiment in FIG. 1 and differs in that the shaft end 7 is connected to the rotor tube via a first flange connection 7a on the non-drive side NDE of the rotor tube 3b 3b is connected, and the drive shaft 11 is connected to the rotor tube 3b on the drive side DE of the rotor tube 3b via the second flange portion 11a. The first flange connection 7a is produced by means of first bolts 7d, and the second flange connection 11a is produced by means of second bolts 11b. Furthermore, the flange connection can preferably additionally be produced by means of welding.

In addition, an optional, coolant-impermeable dividing wall 10 is installed in the rotor tube 3b, the dividing wall being arranged to guide the cooling medium 19 supplied through the shaft end 7 to the cooling opening 3c.

FIG. 3 shows a longitudinal section of a third embodiment of the rotating electrical machine 1 . The third embodiment of the rotating electrical machine 1 basically corresponds to the second embodiment in FIG. 2 and differs in that the additional cooling medium 19a produced by the second heat exchanger 12 is supplied onto the drive side DE. The additional cooling medium 19a is guided in the axial direction into the rotor tube 3b through further parallel holes 11c in the drive shaft 11 and aggregates with the cooling medium 19 in the rotor tube 3b to form a cooling medium 19d supplied on both sides. Thereby, more coolant can be supplied to the rotating electrical machine 1, which results in a greater total cooling power.

FIG. 4 shows a three-dimensional representation of the pod drive 15 . The pod drive 15 has a rotary electric machine 1 , which in its embodiment corresponds, for example, to that in FIG. 1 . The cooling openings 3c are embodied by way of example as elongated holes and are arranged equidistantly in the circumferential direction.

Furthermore, the pod drive 15 has a first bearing arrangement 17 on the non-drive side NDE of the rotary electric machine 1, with which the shaft end 7 is supported. Furthermore, the drive shaft 11 is supported on the drive side DE of the rotary electric machine 1 by means of a second bearing arrangement 18 . The two bearing arrangements 17 , 18 each have at least one radial bearing and an axial bearing. Axial bearings are designed as axial spherical roller bearings or CARB bearings. Thus, the drive shaft 11 and the shaft end 7 each have a support bearing and a guide bearing, which increases the efficiency of the pod drive 15 especially under prevailing marine conditions.

The propeller 13 is connected to the drive shaft 11 of the rotary electric machine 1 on the drive side DE. In operation, the stator lamination stack 2a is also cooled by the water 16 surrounding the pod drive 15 . The housing 20 surrounding the pod drive 15 protects the rotating electrical machine 1 , the bearings 17 , 18 and other components from water 16 intrusion. In order to enable more efficient cooling by the surrounding water 16 during operation, the housing can be recessed at the stator lamination stack 2a. So that the stator lamination stack 2a is in direct contact with the cooling water 16 .

Figure 5 shows a three-dimensional representation of a first embodiment of the shaft end 7 connected to the rotor tube 3b. The shaft end 7 is fixed to the rotor tube 3b via a shrink fit.

In such a shrink-fit portion, the rotor tube 3b is heated, for example, by several hundred degrees Celsius, thereby causing the inner diameter of the rotor tube 3b to increase due to thermal expansion, which is also called thermal expansion. The shaft end 7 is then inserted preferably flush into the heated rotor tube 3b. During cooling of the rotor tube 3b, thermal shrinkage, also referred to as thermal shrinkage, occurs, whereby the rotor tube 3b again assumes the previous dimensions and is connected to the shaft end 7 in a rotationally fixed manner

The shaft end 7 is designed to be substantially thinner than the inner diameter of the rotor tube 3b. Only at the end of the shaft end 7 that is connected to the rotor tube 3 via the aforementioned shrink fit, the shaft end 7 is designed to be thicker than the inner diameter of the rotor tube 3b in the cooled state to achieve stable torsion-resistant hot pressing Cooperate. Parallel holes 7c are arranged in this area so that they do not extend over the entire axial length of the shaft end 7 . Instead, the central hole 7b extends in the axial direction over the entire axial length of the shaft end 7 through the axis of rotation 4 . The central hole 7b is arranged rotationally symmetrically with respect to the axis of rotation 4 . The parallel holes 7c are arranged concentrically about the axis of rotation 4 in the axial direction. The distances of the concentrically arranged parallel holes 7c from each other in the circumferential direction are preferably the same.

FIG. 6 shows a three-dimensional representation of a second embodiment of the shaft end 7 connected to the rotor tube 3b. The second embodiment of the shaft end 7 corresponds substantially to the first embodiment of FIG. 5 and differs in that the shaft end is designed cylindrically, that is to say the shaft end 7 has an almost constant value over its axial length. thickness, and preferably slightly thicker than the inner diameter of the rotor tube 3b in the cooled state, to allow a stable torsion-resistant shrink fit. Both the central hole 7b and the parallel hole 7c extend over the entire axial length of the shaft end 7 in the axial direction. Therefore, for example, a larger inner diameter of the first bearing 17 on the non-drive side NDE is necessary compared to the first embodiment of FIG. 5 .

FIG. 7 shows the vessel 14 with the pod drive 15 . The vessel 14 is in the water 16 so that the pod drives 15 are below the water surface. The pod drive 15 has a rotary electric machine 1 with a drive shaft 11 and a propeller 13 . The propeller 13 is mounted on the rear of the pod drive 15 as a propulsion propeller, but can also be mounted on the front of the pod drive 15 as a traction propeller. The first heat exchanger 5 is located outside the pod drive 15 in the hull of the vessel 14 and supplies a cooling medium 19 to the pod drive. The outflowing cooling medium 19c, which is heated compared to the supplied cooling medium 19, is directed in the opposite direction to the first heat exchanger 5, which again cools the outflowing cooling medium 19c. Since the first heat exchanger 5 is not in the pod drive 15, space is saved and the pod drive 15 can be made more compact.

To sum up, the present invention relates to a rotary electric machine 1 with a rotor 3 rotatable about an axis of rotation 4, having a rotor tube 3b and a shaft end 7, wherein the shaft end 7 is arranged on the non-drive side NDE of the rotary electric machine 1, And therein, the rotor tube 3b is mechanically connected with the shaft end 7 at the axial end of the rotor tube 3b. It is proposed to save space and costs that the shaft end 7 has a central bore 7b and/or parallel bores 7c which are provided for supplying a cooling medium 19 into the rotor tube 3b.

Claims (21)

1. A rotary electric machine (1) having: a rotor (3) rotatable about an axis of rotation (4), the rotor having a rotor tube (3b) and a shaft end (7); and, surrounding the rotor (3) ) of the stator (2); and an air gap (6) between the rotor (3) and the stator (2), wherein the rotor (3) has a rotor lamination stack (3a) surrounding the rotor tube (3b), wherein the shaft end (7) is arranged on the non-drive side (NDE) of the rotating electrical machine (1), wherein the rotor tube (3b) is mechanically connected to the shaft end (7) at the axial end of the rotor tube (3b), Wherein, the shaft end (7) has a central hole (7b) and a parallel hole (7c), The central hole and the parallel holes are provided for supplying a cooling medium (19) into the rotor tube (3b), wherein the rotor tube (3b) has at least one cooling opening (3c), and wherein the central hole (7b) and the parallel hole (7c) are fluidically connected to the at least one cooling opening (3c), wherein the rotor tube (3b) and the rotor lamination stack (3a) have at least one cooling opening (3c) extending in the radial direction in the axial center of the rotor tube and the rotor lamination stack, and Therein, the cooling opening (3c) is provided for guiding the cooling medium (19) supplied into the rotor tube (3b) through the shaft end (7) to the air gap (6) and at the Between the rotor tubes (3b) and the rotor laminations (3a) are led to the axial ends of the rotor (3) and the cooling medium (19b) which is then led is led in the radial direction past the stator Winding heads ( 2 b ) from which the cooling medium flowing out is guided from both sides through the stator lamination stack ( 2 a ) and converges in the axial center of the stator lamination stack ( 2 a ). 2. A rotating electrical machine (1) according to claim 1, wherein the central hole (7b) is arranged to extend in the axial direction along the axis of rotation (4). 3. The rotating electrical machine (1) according to claim 1, wherein the parallel holes (7c) are arranged to extend in the axial direction around the axis of rotation (4). 4. The rotating electrical machine (1) according to claim 1, wherein the shaft end (7) is connected to the rotor tube via a first shrink fit (7e) or via a first flange connection (7a) (3b) Connection. 5. A rotating electrical machine (1) according to claim 1, wherein the rotor lamination stack (3a) has at least one permanent magnet (21) arranged to pass through the air gap (6) The cooling medium (19b) is guided for cooling. 6 . The rotating electrical machine ( 1 ) according to claim 5 , wherein the permanent magnets ( 21 ) have a rare earth element fraction, wherein the permanent magnets ( 21 ) are provided to be cooled during operation to between 70° C. and temperature between 100°C. 7 . The rotating electrical machine ( 1 ) according to claim 6 , wherein the permanent magnets ( 21 ) have a dysprosium fraction, wherein the permanent magnets ( 21 ) are provided to be cooled to 80° C. to 90° C. during operation. 8 . temperature between °C. 8. A rotating electrical machine (1) according to claim 1, wherein the stator (2) has stator winding heads (2b) at the axial ends, wherein the shaft is guided to the rotor (3) A cooling medium (19b) towards the ends is provided for cooling the stator winding heads (2b). 9. The rotating electrical machine (1) according to claim 1, wherein the rotor tube (3b) has a thickening (3d) surrounding the cooling opening (3c), the thickening (3d) being provided Used to improve the rigidity of the rotor tube (3b). 10. A rotating electrical machine (1) according to claim 1, wherein the rotor tube (3b) has a coolant-impermeable dividing wall (10) provided for passing through the shaft end (10). 7) The supplied cooling medium (19) is led to the cooling opening (3c). 11. A rotating electrical machine (1) according to claim 1, which has a first guide plate (8) provided for a cooler supply through the shaft end (7) A separation is achieved between the cooling medium (19) of the rotor (19) and the cooling medium (19b) directed to the axial ends of the rotor (3). 12. A rotating electrical machine (1) according to claim 1, having a drive shaft (11) arranged on a drive side (DE) of the rotating electrical machine (1), wherein the Said drive shaft (11) has further parallel holes (11c) provided for supplying additional cooling medium (19a) into said rotor tube (3b). 13. The rotating electrical machine (1) according to claim 12, wherein the drive shaft (11) is connected to the rotor tube via a second shrink fit (11d) or via a second flange connection (11a) (3b) Connection. 14. Rotary electric machine (1) according to claim 12 or 13, which has a second guide plate (9) provided for in A separation is achieved between the additional cooling medium (19a) and the cooling medium (19b) directed to the axial ends of the rotor (3). 15. A pod drive having: at least one rotary electric machine (1) according to any one of claims 1 to 14; on the non-drive side of the rotary electric machine (1) a first bearing arrangement (17) on (NDE); a second bearing arrangement (18) on the drive side (DE) of the rotating electrical machine (1); and a propeller (13), wherein the propeller (13) is connected to the drive shaft (11) of the rotating electrical machine (1). 16. The pod drive (15) according to claim 15, wherein the first bearing arrangement (17) and/or the second bearing arrangement (18) each have at least one radial bearing and an axial bearing . 17. A vessel (14) having at least one pod drive (15) according to any one of claims 15 or 16 and a first heat exchanger arranged outside the pod drive (15) an exchanger (5), wherein the first heat exchanger (5) is arranged to supply a cooling medium (19) to the pod drive and to recool the cooling medium (19) flowing out of the pod drive (15) 19c). 18. A method for cooling a rotating electrical machine (1) according to any one of claims 1 to 14, wherein the cooling medium (19) first passes through the central hole (7b) of the shaft end (7) and /or parallel holes (7c) are guided in the axial direction into the rotor tubes (3b), after which the cooling medium is guided in the radial direction through the rotor tubes (3b) and the rotor laminations arranged in the rotor tubes (3b) Cooling openings (3c) in the axial center of the group (3a), after which the cooling medium (19b) is guided through the air gap (6) and/or between the rotor tubes (3b) and the rotor laminations Between the groups (3a) are directed to the axial ends of the rotor (3) and after that the directed cooling medium (19b) is directed in the radial direction past the stator winding heads (2b). 19. Method according to claim 18, wherein the guided cooling medium (19b) is directed symmetrically and almost uniformly distributed to the axial ends of the rotor (3) and to the stator winding heads (2b) . 20. The method according to claim 19, wherein the cooling medium (19c) flowing out of the stator winding heads is guided from both sides through the stator lamination pack (2a) and at the axis of the stator lamination pack (2a) Aggregate to the center. 21. The method according to any one of claims 18 to 20, wherein the additional cooling medium (19a) is guided in the axial direction through further parallel holes (11c) of the drive shaft (11) to the in the rotor tube (3b), and the cooling medium (19) and the additional cooling medium (19a) are aggregated in the rotor tube (3b) into a cooling medium (19d) supplied on both sides.

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